In the field of communications, Quality-of-Service (QoS) is used to characterize the user's communication experience. Good QoS characterizes a positive user experience where all communications arrive on time and are uncorrupted. Poor QoS characterizes a negative user experience where some communications arrive late or corrupted. QoS is controlled by the communication resources that the communication system allocates to the user. These communication resources include the communication links and equipment that make up the communication path. For example, a congested communication path typically provides poor QoS when compared to a lightly loaded communication path. In addition, a communication path with several intermediate processing nodes provides poor QoS when compared to a communication path with fewer processing nodes. Many other factors affect QoS, such as the speed of the communication links or the processing capacity of the nodes.
Communication systems typically allow a user to specify a QoS when they request a communication service. In some cases, the user may desire to pay more for high QoS that is provided by premium network nodes and links. In other cases, the user may desire to pay less for lower but adequate QoS that is provided by cheaper network nodes and links.
The ability of the user to control QoS during a communication session is limited. In some cases, the communication network may detect a problem during the session and reroute user traffic to improve poor QoS. In other cases, the user may terminate a communication session with poor QoS and request a new communication session with higher QoS. This is not an effective technique for allowing the users in a communication session to conveniently and dynamically control QoS during the session.